diff --git a/javascript/net/grpc/web/genericclient.js b/javascript/net/grpc/web/genericclient.js
new file mode 100644
index 000000000..275149ebe
--- /dev/null
+++ b/javascript/net/grpc/web/genericclient.js
@@ -0,0 +1,29 @@
+/**
+ * @fileoverview base interface for grpc web GenericClient.
+ */
+
+goog.module('grpc.web.GenericClient');
+goog.module.declareLegacyNamespace();
+
+const Metadata = goog.require('grpc.web.Metadata');
+const MethodDescriptor = goog.require('grpc.web.MethodDescriptor');
+const UnaryResponse = goog.require('grpc.web.UnaryResponse');
+
+/**
+ * @interface
+ */
+const GenericClient = function() {};
+
+
+/**
+ * @param {!REQUEST} request The request proto message
+ * @param {!MethodDescriptor<REQUEST, RESPONSE>} methodDescriptor Information of
+ *     this RPC method
+ * @param {!Metadata} metadata The user defined request metadata.
+ * @return {!Promise<!UnaryResponse<RESPONSE>>} A promise that resolves to the
+ *     response message
+ * @template REQUEST, RESPONSE
+ */
+GenericClient.prototype.unaryCall = goog.abstractMethod;
+
+exports = GenericClient;
diff --git a/javascript/net/grpc/web/metadata.js b/javascript/net/grpc/web/metadata.js
new file mode 100644
index 000000000..27dcaa555
--- /dev/null
+++ b/javascript/net/grpc/web/metadata.js
@@ -0,0 +1,15 @@
+/**
+ * @fileoverview grpc-web request/response metadata.
+ *
+ * Request and response headers will be included in the Metadata.
+ */
+
+goog.module('grpc.web.Metadata');
+goog.module.declareLegacyNamespace();
+
+/**
+ * @typedef {!Object<string,string>}
+ */
+let Metadata;
+
+exports = Metadata;
diff --git a/javascript/net/grpc/web/unaryresponse.js b/javascript/net/grpc/web/unaryresponse.js
new file mode 100644
index 000000000..a17879ba3
--- /dev/null
+++ b/javascript/net/grpc/web/unaryresponse.js
@@ -0,0 +1,25 @@
+/**
+ * @fileoverview gRPC web client UnaryResponse returned the by grpc unary calls.
+ * It consists of response message and response metadata(headers).
+ */
+
+goog.module('grpc.web.UnaryResponse');
+goog.module.declareLegacyNamespace();
+
+const Metadata = goog.require('grpc.web.Metadata');
+
+/**
+ * @constructor
+ * @struct
+ * @template RESPONSE
+ * @param {RESPONSE} message
+ * @param {!Metadata=} metadata
+ */
+const UnaryResponse = function(message, metadata) {
+  /** @const {RESPONSE} */
+  this.message = message;
+  /** @const {!Metadata|undefined} */
+  this.metadata = metadata;
+};
+
+exports = UnaryResponse;